for ‧ mi ‧ da ‧ ble /ˈfɔːmədəb ə l, ˈfɔːmɪdəb ə l, fəˈmɪd- $ ˈfɔːr-/ BrE AmE adjective
[ Date: 1300-1400 ; Language: Latin ; Origin: formidabilis , from formido 'fear' ]
1 . very powerful or impressive, and often frightening:
The building is grey, formidable, not at all picturesque.
The new range of computers have formidable processing power.
2 . difficult to deal with and needing a lot of effort or skill
formidable task/challenge
the formidable task of local government reorganization
—formidably adverb